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A father’s weight before a child is conceived can impact their baby’s birth weight, new Canadian-led research says.
An international team of researchers reviewed 17 studies from around the world that looked at the relationship between a father’s body mass index (BMI) before a child is conceived and the child’s birth weight.
Twelve of the studies showed a “significant association” between the two.
Fathers with higher body mass indexes were more likely to father children who had high birth weights.
High baby birth weight can increase the likelihood that a mother will need an emergency C-section or bleed after giving birth.
Children who are born with high birth weights are also at greater risk for becoming obese or developing metabolic problems.
“We know that mothers’ weight at conception is a risk factor [for high birth weight],” said Cindy-Lee Dennis, a senior author of the study and professor of nursing at the University of Toronto.
“But now there’s growing evidence to suggest that fathers’ weight at conception is an important indicator for pregnancy and child outcomes.”
True in humans
Bernard Robaire, a pharmacology professor at McGill University who researches how the environment impacts male fertility, says research with animals has shown obese or overweight fathers are more likely to have children who are also obese or overweight.
Sperm can carry markers associated with obesity, says Robaire, who was not part of Dennis’ study.
The same trend is true in humans.
“In humans, there’s clearly a preponderance of increased obese children of fathers who are obese, but you have to take into account potentially other factors,” he said.
Factors such as the home environment may also have an impact. For example, it is likely that fathers and children are eating similar food, so if there is unhealthy food at home, children are likely to eat it.
‘A lot can happen’
A father’s health can impact children in many ways, says Dennis.
Research has shown a connection between environmental pollutants fathers are exposed to before a child is conceived and the health of the baby.
The research study also found evidence suggesting that fathers who have diabetes and metabolic syndromes are more likely to father children with low birth weights.
Infants born with low birth weights are more likely to die in infancy and are at greater risk of developing physical, developmental, cognitive or mental disabilities.
“This aligns with research indicating that paternal conditions may contribute to low birth weight by influencing fetal development and placental health,” the study says.
Studying the health of fathers before conception is important, says Dennis. While women are born with a fixed number of eggs, men produce sperm throughout their lifetime. It takes sperm about three months to develop, so changes in lifestyle can have an impact on the health of sperm.
“A lot can happen with that sperm,” says Dennis. “We can improve the quality of that sperm pre-conceptionally.”
Canada is currently developing its first federal men’s health strategy. This strategy should consider men’s health before, during and after their children are born, says Dennis.
“We have undervalued the role of the father in progeny and the children,” said Robaire. More systematic studies on the topic are needed, he says.
Dennis agrees. “It’s not just the moms that impact child’s development and growth trajectories [and] pregnancy outcomes,” said Dennis.
“[Fathers] matter too.”
